1. Pathology of the Immune Response in Lymphatic Tissues
Peripheral lymphatic tissues ("lymphoid tissues") provide the environment for generation of a specific immune response to certain antigens when the lymphoid tissues are extra-regional to or draining a principal source of the antigen. In particular, cellular proliferation in lymphoid tissues has been noted in certain pathological conditions including solid, non-lymphoid tumors, and Leishmaniasis. 1.1 Solid, non-lymphoid tumors
The response of an individual to tumor cells involves the reactions and counteractions mediated by both cellular and humoral arms of the immune system. Tumor cell growth may represent a disturbance in the equilibrium of the immune system that is pre-existing, and/or induced by the tumor cells themselves. However, most investigations to date have focused on the role of T cells in tumor immunity. The role of B cells in a tumor-bearing individual still remains unclear. Previous studies have shown that lymph nodes and other lymphoid tissues extra-regional to a primary solid non-lymphoid tumor in cancer patients, and in vivo experimental animal models of tumor development, can undergo a prominent cellular expansion in the germinal centers of the tissue (see, e.g., Eremin et al., 1980, Br. J. Cancer 41:62; Bertschmann et al., 1984, Br. J. Cancer 49:477-484). Such lymphoid tissues contain immune cells that include B lymphocytes (B cells). However, the reason(s) for this observed B cell proliferative response remains unclear, and has been hypothesized be due to either activation and stimulation directly by tumor cells, and/or indirectly by stimulation of T-helper cells which then activate and stimulate B cells.
Such B cells appear to be able to elicit anti-tumor immunity. In that regard, there are numerous reports that cancer patients have circulating antitumor antibodies (see, e.g., Carey et al., 1976, Proc. Natl. Acad. Sci. USA 73:3278-3282; Abe et al., 1989, Cancer Res. 80:271-276; Christensen et al., 1989, Int. J. Cancer 37:683-688). Thus, it appears that a humoral immune response towards tumor-associated antigens can be mounted in cancer patients. However, the roles of B cells, tumor associated antigens, and lymphoid tissues containing B cells, in the host response to tumor remain poorly defined.